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i2c-i801: Use usleep_range to wait for command completion 

Use usleep_range instead of msleep when waiting for command
completion. Most SMBus commands complete in less than 2 jiffies so
this brings a pleasant performance boost.

Strongly inspired from a similar change by Olivier Sobrie to the
i2c-isch driver.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Olivier Sobrie <olivier@sobrie.be>
This commit is contained in:
Jean Delvare 2012-03-26 21:47:19 +02:00 committed by Jean Delvare
parent 062737fb6d
commit 84c1af4c21
1 changed files with 12 additions and 12 deletions
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24
drivers/i2c/busses/i2c-i801.c
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@ -2,7 +2,7 @@
Copyright (c) 1998 - 2002 Frodo Looijaard <frodol@dds.nl>,
Philip Edelbrock <phil@netroedge.com>, and Mark D. Studebaker
<mdsxyz123@yahoo.com>
Copyright (C) 2007, 2008 Jean Delvare <khali@linux-fr.org>
Copyright (C) 2007 - 2012 Jean Delvare <khali@linux-fr.org>
Copyright (C) 2010 Intel Corporation,
David Woodhouse <dwmw2@infradead.org>
@ -106,7 +106,7 @@
#define SMBHSTCNT_KILL 2
/* Other settings */
#define MAX_TIMEOUT 100
#define MAX_RETRIES 400
#define ENABLE_INT9 0 /* set to 0x01 to enable - untested */
/* I801 command constants */
@ -217,7 +217,7 @@ static int i801_check_post(struct i801_priv *priv, int status, int timeout)
dev_dbg(&priv->pci_dev->dev, "Terminating the current operation\n");
outb_p(inb_p(SMBHSTCNT(priv)) | SMBHSTCNT_KILL,
SMBHSTCNT(priv));
msleep(1);
usleep_range(1000, 2000);
outb_p(inb_p(SMBHSTCNT(priv)) & (~SMBHSTCNT_KILL),
SMBHSTCNT(priv));
@ -274,11 +274,11 @@ static int i801_transaction(struct i801_priv *priv, int xact)
/* We will always wait for a fraction of a second! */
do {
msleep(1);
usleep_range(250, 500);
status = inb_p(SMBHSTSTS(priv));
} while ((status & SMBHSTSTS_HOST_BUSY) && (timeout++ < MAX_TIMEOUT));
} while ((status & SMBHSTSTS_HOST_BUSY) && (timeout++ < MAX_RETRIES));
result = i801_check_post(priv, status, timeout > MAX_TIMEOUT);
result = i801_check_post(priv, status, timeout > MAX_RETRIES);
if (result < 0)
return result;
@ -293,12 +293,12 @@ static void i801_wait_hwpec(struct i801_priv *priv)
int status;
do {
msleep(1);
usleep_range(250, 500);
status = inb_p(SMBHSTSTS(priv));
} while ((!(status & SMBHSTSTS_INTR))
&& (timeout++ < MAX_TIMEOUT));
&& (timeout++ < MAX_RETRIES));
if (timeout > MAX_TIMEOUT)
if (timeout > MAX_RETRIES)
dev_dbg(&priv->pci_dev->dev, "PEC Timeout!\n");
outb_p(status, SMBHSTSTS(priv));
@ -382,12 +382,12 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
/* We will always wait for a fraction of a second! */
timeout = 0;
do {
msleep(1);
usleep_range(250, 500);
status = inb_p(SMBHSTSTS(priv));
} while ((!(status & SMBHSTSTS_BYTE_DONE))
&& (timeout++ < MAX_TIMEOUT));
&& (timeout++ < MAX_RETRIES));
result = i801_check_post(priv, status, timeout > MAX_TIMEOUT);
result = i801_check_post(priv, status, timeout > MAX_RETRIES);
if (result < 0)
return result;